The Effect of Evidential Impact on Perceptual Probabilistic Judgments

Abstract

In a series of three behavioral experiments, we found a systematic distortion of probability judgments concerning elementary visual stimuli. Participants were briefly shown a set of figures that had two features (e.g., a geometric shape and a color) with two possible values each (e.g., triangle or circle and black or white). A figure was then drawn, and participants were informed about the value of one of its features (e.g., that the figure was a “circle”) and had to predict the value of the other feature (e.g., whether the figure was “black” or “white”). We repeated this procedure for various sets of figures and, by varying the statistical association between features in the sets, we manipulated the probability of a feature given the evidence of another (e.g., the posterior probability of hypothesis “black” given the evidence “circle”) as well as the support provided by a feature to another (e.g., the impact, or confirmation, of evidence “circle” on the hypothesis “black”). Results indicated that participants’ judgments were deeply affected by impact, although they only should have depended on the probability distributions over the features, and that the dissociation between evidential impact and posterior probability increased the number of errors. The implications of these findings for lower and higher level cognitive models are discussed.

Question-answer dynamics and confirmation theory in reasoning by representativeness

“…The fact that Mangiarulo et al (2021) found an effect without structure while we didn't is informative. Besides seeing the distribution only quite briefly, their participants did not know, when looking at the distribution, what the evidence would be, or what dimension they would be asked about.…”

“…It's interesting to note that an independent study (Mangiarulo et al, 2021), looking at effects of evidential impact on perceptual probabilistic judgment, found an effect of confirmation theory in a design that shares some properties with our flat condition. The experiment by Mangiarulo et al (2021) involved a two-step process. First, participants saw shuffled sets of about 30 elements of two possible shapes and two possible colors.…”

Effects of causal structure and evidential impact on probabilistic reasoning

“…It varies across conditions the direction and evidential impact of the evidence, the causal status of the base-rate information, and the causal status of the evidence. This allows us to compare the merits of the Causal Bayesian Reasoner theory, the Evidential Impact Reasoner theory, and a third possibility, prompted by the suggestion that confirmation-theoretic reasoning strategies are triggered by a search for causal explanations of phenomena (Mangiarulo, Pighin, Polonio, & Tentori, 2021), as we detail shortly. Subjects were told to consider a fictional story about an ancient Mesopotamian village.…”

What Can the Conjunction Fallacy Tell Us about Human Reasoning?

“…These results are consistent with those from the category-based induction literature, according to which adults, and even children as young as 5, when evaluating argument strength, follow popular principles of evidential impact, such as the similarity between premises and conclusion and the diversity of premises (Heit and Hahn, 2001;Lo et al, 2002;Lopez et al, 1992;Osherson et al, 1990;Zhong et al, 2014). The spontaneous, and often implicit, appreciation of evidential impact has been shown, often under other names, to play a fundamental role in a variety of other higher-and lower-level cognitive processes, including causal induction (Cheng and Novick, 1990;Cheng, 1997), conditional reasoning (Douven and Verbrugge, 2012;Krzyzanowska et al, 2017), learning (Danks, 2003), language processing (Bhatia, 2017;Bullinaria and Levy, 2007;Nadalini et al, 2018;Paperno et al, 2014), and even perception (Mangiarulo et al, 2019).…”